Sheet packages, packages covering a stack of printer sheets with a package member, have been well known today. A sheet package is opened by a user purchasing the package and then set in a printer. Such sheet packages allow users to handle numbers of sheets in a mass, package by package, providing improved usability of sheets. The sheet packages, covering and protecting the sheets with a package member, are especially useful for heat-sensitive sheets which are susceptible to light and heat.
In recent years, with the ongoing miniaturization of personal computers and prevalence of PDAs (Personal Digital Assistants), printers that are small-sized and portable are in great and increasing demand. With such small-sized printers, especially with printers supporting small sheets of the post card size or less, the handling of sheets is not simple and easy and thus the use of sheet packages (covering a stack of sheets with a package member) is desired.
However, in such a small-sized printer, a sheet package loaded in the printer can shift from its normal position due to vibration during carriage, etc., hampering normal printing. Therefore, a sheet package not easily undergoing the displacement in the printer has been sought after.